(11) باب ذِكْرُ الْعَبَّاسِ بْنِ عَبْدِ الْمُطَّلِبِ رضى الله عنه
Narrated Anas:
Whenever there was drought, `Umar bin Al-Khattab used to ask Allah for rain through Al-`Abbas bin `Abdul Muttalib, saying, "O Allah! We used to request our Prophet to ask You for rain, and You would give us. Now we request the uncle of our Prophet to ask You for rain, so give us rain." And they would be given rain."
Reference: Sahih al-Bukhari 3710
In-book reference: Book 62, Hadith 61
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 5, Book 57, Hadith 59